ML20212D429

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Forwards Required 30-day Written Event Rept Re Criticality Accident Alarm Sys Response Time in Bldg C-710.Encl 2 Contains Commitments Contained in Submittal
ML20212D429
Person / Time
Site: Paducah Gaseous Diffusion Plant
Issue date: 09/17/1999
From: Pulley H
UNITED STATES ENRICHMENT CORP. (USEC)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GDP-99-1033, NUDOCS 9909230118
Download: ML20212D429 (7)


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USEC A Global Energy Company l

September 17,1999 GDP 99-1033 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Paducah Gascous Diffusion Plant (PGDP)

Docket No. 70-7001 Event Report ER-99-13 Pursuant to 10CFR76.120(d)(2), enclosed is the required 30-day written event report pertaining to the Criticality Accident Alarm System (CAAS) response time in Building C-710. The Nuclear Regulatory Commission Headquarters (NRC-HQ) operations office was notified of the event on August 22,1999 (NRC No. 36057). Commitments contained in this submittal are identified in.

Any questions regarding this matter should be directed to Larry Jackson at (502) 441-6796.

Sincerely, 1

kIowar Pulley General Manager Paducah Gaseous Diffusion Plant

Enclosures:

As Stated cc: NRC Region III Office NRC Resident Inspector-PGDP W

<Y 9909230118 990917

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PDR ~ ADOCK 07007001

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C PDR-PO. Box 1410, Paducah, KY 42001 Telephone 502-441-5803 Fax 502-441-5801 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC

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Docket No. 70-7001 L

GDP 99-1033 i

Page 1 of 5 EVENT REPORT ER-99-13

- DESCRIPTION OF EVENT l

On ' August 21~,1999, at approximately 1824 hrs., the Plant Shift Superintendent (PSS) was notified that during testing of new 30-watt AC/DC Criticality Accident Alarm System (CAAS) horns, in

. Building C-746-Q, the homs did not successfully pass the testing criteria for horn actuation response time of 0.5 seconds, as required by ANSl/ANS Standard 8.3 - 1986. At the time of the testing in Building C-746-Q, the new CAAS horns were not in service and the building remained under the old CAAS system, which remained operable. As a result of the testing in Building C-746-Q and the recognition that the Building C-710 CAAS system used the same 30-watt AC/DC horn, additional testing was performed on August 21,1999, on the Building C-71015-watt AC and 30-watt AC/DC horns. This additional testing indicated that the 30-watt AC/DC horns could not meet the 0.5 seconds time response; however, the 15-watt AC horns did meet the required time response. As a result, on August 21, 1999, at approximately 1955 hrs., the PSS declared the Building C-710 CAAS inoperable and entered the Limiting Conditions for Operation (LCO). On August 22,1999, at 0830 hrs., the. Nuclear Regulatory Commission Headquarters (NRC-HQ) operations office was notified of the event in accordance with 10CFR 76.120(c)(2) (NRC No.

~ 36057).

Prior to 1995, the plan' CAAS horns were the Edwards model 5530-B-N5. In 1995, Safety System t

Inspection Plan 06-999-8310, for electronic horns purchased in accordance with DS-CIE-16289-90, was revised to include a new Edwards model 5530-B-Y6 to the list of acceptable CAAS horns.

The new model horns were considered to be identical to previously accepted models, except that they were designed to function over the full range of 120-240 VAC or VDC. Neither the time response specifications, nor requirements for horn time response testing were included in the specifications for procurement of the Edwards model 5530-B-Y6 horn. It was assumed the Edwards model 5530-B-Y6 would meet the same requirements, because the Edwards model 5530-B-N5 hom had met the time response requirements for an installed CAAS.

On March 8,1996, Engineering Service Order (ESO) Z95820 was initiated to upgrade the Building C-710 CAAS. Analysis indicated that the CAAS building coverage and audibility levels for the building were inadequate. Systems Requirement Document (SRD), ESO Z95820, performance requirements, stated that "the alarm.must sound within 0.5 seconds of the start of the initiating

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event."' Design Analysis and Calculations (DAC) Z-95820-3, "LMUS Direction That Alarm Horn Coverage Be Provided For an Area Within 200 Feet of Building C-710" stated that each vendor contacted could supply a horn that would respond within 0.5 seconds.

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Docket No. 70-7001 GDP 99-1033 Page 2 of 5 In 1997, Engineering Specification' Data Sheet (ESDS) DS-CIE-16289-262, " Electronic Alarm Horn Watt," and DS-CIE-16289-90, " Electronic Alarm Horn Watt" were issued. The ESDS identifies requirements for procurement and acceptance. Neither data sheet specified a maximum response time ofless than 0.5 seconds for the homs.

Maintenance Work Package R 9801216-16 was used to document the functional testing for the Building C-710 CAAS project for the five newly installed CAAS clusters and horns. The work package's task description stated, " perform functional / final test for C-710 CAAS project, (5) newly installed clusters." The description of the work performed indicated that on June 28,1998, a functional test was successfully performed in accordance with procedure CP4-GP-IM6239, "C-710 Criticality Accident Alarm System Annual Cluster Replacement and Functional Tests" Section 8.2, for clusters AM, AN, AP, AQ, and AR. On June 29,1998, under this same work package, response time for Building C-710 CAAS design was verified using cluster "AP" with a 15-watt AC hom with acceptable results. This test was performed in accordance with CP4-GP-IM6496,

" Response Time for Criticality Accident Alarm System."

Section 9, " Acceptance Criteria" specifies that an alarm signal shall be produced within 0.5 seconds after initiation.

The new CAAS horns installed in Buildings C-709/710 are of the same manufacture and basic model number; however, some are 15-watt AC and some are 30-watt AC/DC design. At the time of installation, the 30-watt AC/DC CAAS horns were not tested for response time prior to installation. A number of the installed.15-watt AC horns were tested and demonstrated an acceptable response time in accordance with the ANSI /ANS standards. At the time ofinstallation, I

the potential'for a deviation in horn activation response time between the 15-watt and 30-watt horns was not recognized and the 30-watt AC/DC horns were not tested.

i A questioning attitude would have helped determine the existence of a deficiency in the ESDS or

. system testing relative to alarm horn response times. If the 30-watt AC/DC horn response times had been tested, the deviation in actuation times in the two Edwards horn models would have been identified.

The safety significance of exceeding the 0.5 seconds time delay in the actuation of the CAAS horns is considered minimal for the following reasons:

1. On August 23, 1999, Engineering Notice EN-C-832-99-037, Rev. O, " Additional Dose Received.By Evacuating Personnel Due To A Delay In CAAS Horn Actuation" was
published. The evahmtion concluded that the effect of a 1.5 seconds, or less delay beyond the 0.5 seconds allowed by ANS/ ANSI Standard 8.3 in the actuation of the CAAS horn on the dose received by' personnel during evacuation was not significant. On August 24,1999, Health Physics conducted a review of the EN and concluded that there was no increase in consequences due to the additional delay of CAAS horn actuation for 1.5 seconds.

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o Docket No. 70-7001 GDP 99-1033 Page 3 of 5

2. On August 25, 1999, Engineering published Engineering Evaluation EV-C-813-99-006, Rev 0, "CAAS Electronic Horn Response Time Test Results (ATRC-99-4990; ATRC 4996).". The EV concluded that a time response to a CAAS alarm can be as much as 1.258 seconds (based on test data) up to 1.758 seconds (based on test data and conversations with

- the vendor). To encompass unknowns, such as how the horn time response will react due to environmental conditions, it was recommended that a maximum 2-second response to a CAAS be implemented.

3. On August 25, 1999, Engineering published Engineering Evaluation EV-C-812-99-010, Rev. O, " Evaluation OfImpact of CAAS Alann Horns With Response Times Greater Than 0.5 seconds." The EV concluded that based on a statistical sample testing of the 15-watt AC and 30-watt AC/DC CAAS horns in Building C-710, all of the horns tested allow the system to meet the requirement response time of 2.0 seconds based on the Request For Application Change (RAC) 99C054, Rev. 0, which was approved in accordance with

' 10CFR76.68.

CAUSE FOR THE EVENT A. Direct Cause The direct cause for this event was a failure to include response time testing of the 30-watt CAAS horns in the ESDS, or include the 30-watt horns in the system acceptance testing to assure operability within 0.5 seconds.- At the time ofinstallation, Engineering did not anticipate that a deviation existed in the CAAS horn's activation response times between the 15-watt and 30-watt horns.

B. Root Cause The root cause for this event was an erroneous assumption that the Edwards model 5530-B-Y6 CAAS horn would respond within 0.5 seconds, as existing Edwards model 5530-B-N5 CAAS horns had done. This erroneous assumption resulted in inadequate design testing and control of a critical CAAS horn design characteristic.

CORRECTIVE ACTIONS A. Completed Corrective Actions

1. On August 23,1999, Engineering published EN-C-832-99-037, Rev. O, " Additional Dose Received By Evacuating Personnel Due To Delay In CAAS Horn Actuation," which analyzes why the risk is minimal despite a small increase in horn actuation time.

r-Docket o. 70-7001 O JP 99-1033 Page 4 of 5

2. On August 25, 1999, Engineering published Engineering Evaluation EV-C-813-99-006, 2

Rev. O, "CAAS Electronic Horn Response Time Test Results (ATRC-99-4990 and ATRC-99-4996)," which shows the CAAS horns meet the newly approved response time of 2.0 seconds.

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3. On August 25,1999, The Plant Operations Review Committee (PORC) approved a Request for Application Change (RAC 99C054) in accordance with 10CFR76.68, which changed the Safety Analysis Report (SAR) to accept a CAAS alarm signal within 2 seconds of reaching the alarm setpoint.
4. On August 25,1999, Engineering and Maintenance selected and tested a statistical sample of the 15-watt AC and 30-watt AC/DC CAAS horns in Building C-710 in accordance with UE2-BM-PC1038, Rev. O, Change B, " Dedication Of Commercial Grade Items" and CP4-GP-IM6496, " Response Time Testing For Criticality Accident Alarm System, Rev. O. All 15 watt AC and 30-watt AC/DC horns in the sample performed within the 2.0 second requirement.
5. On September 2,1999, Engineering revised the following ESDS to add the requirement for a 100 percent test of CAAS horns to verify a maximum response time of 1.5 seconds, or i

less:

a. DS-CIE-16289-90, Rev. 5, " Electronic Alarm Horn, AC,15-Watt."
b. DS-CIE-16289-262, Rev. 2, " Electronic Alarm Horn, AC/DC,30-Watt."
c. DS-CIE-16289-301, Rev. 2, " Electronic Alarm Horn, AC/DC,15-Watt."

B. Planned Corrective Actions

1. By November 16, 1999, Engineering will complete a crew briefing for appropriate personnel that will encompass the results of this event and reemphasize the need for a questioning attitude.
2. By March 17,2000, Engineering will revise CP2-EG-EG1046, " Design Change Process" to provide additional guidance on development and performance of modification acceptance

' testing of all variations of the design to ensure inputs are met.

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f Docket No. 70-7001 GDP 99-1033 l

Page 5 of 5 l

EXTENT OF EXPOSURE OF INDIVIDUALS TO RADIATION OR RADIOACTIVE I

MATERIAL I

None LESSONS LEARNED i

Testing must be performed on all variations in the configuration of systems, structures, and components to demonstrate that the installed modification will function as the design intended.

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4 Docket No. 70-7001 GDP 99-1033 Page1ofI List of Commitments Event Report ER-99-13

1. By November 16, 1999, Engineering will complete a crew briefing for appropriate personnel that will encompass the results of this event and reemphasize the need for a questioning attitude.
2. By March 17,2000, Engineering will revise CP2-EG-EG1046, " Design Change Process" to provide additional guidance on development and performance of modification acceptance testing of all variations of the design to ensure inputs are met.

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